DAC1408D650HW/C1 NXP [NXP Semiconductors], DAC1408D650HW/C1 Datasheet - Page 27

• Manufacturer Part Number: DAC1408D650HW/C1
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
DAC1408D650_1
Objective data sheet
10.9.1.1 External regulation
10.9.1 Regulation
10.9.2 Full-scale current adjustment
10.9 Full-scale current
Figure 13
integrates an internal bandgap reference voltage which delivers a 1.25 V reference to the
GAPOUT pin. It is recommended to decouple pin GAPOUT using a 100 nF capacitor.
The reference current is generated via an external resistor of 910
pin VIRES. A control amplifier sets the appropriate full-scale current (I
(see
This configuration is optimum for temperature drift compensation because the bandgap
reference voltage can be matched to the voltage across the feedback resistor.
The DAC current can also be set by applying an external reference voltage to the
non-inverting input pin GAPOUT and disabling the internal bandgap reference voltage
with GAP_PD (register 00h[0]; see
description”).
The default full-scale current (I
user to both DACs independently via the serial interface from 1.6 mA to 22 mA, +/- 10 %.
The settings applied to DAC_A_GAIN_COARSE[3:0] (register 0Ah; see
“DAC_A_CFG_2 register (address 0Ah) bit description”
“DAC_A_CFG_3 register (address 0Bh) bit
COARSE[3:0] (register 0Dh; see
description”
description”) define the coarse variation of the full-scale current (see
coarse
Fig 13. Internal reference configuration
Figure 13 “Internal reference
adjustment”).
shows the internal configuration. The DAC1408D650 reference circuitry
and register 0Eh; see
Rev. 01 — 26 May 2009
AGND
AGND
Dual 14-bit DAC, up to 650 Msps, 2 and 4 interpolating
O(fs)
Table 32 “DAC_B_CFG_2 register (address 0Dh) bit
100 nF
910
(1 %)
) is 20 mA but further adjustments can be made by the
configuration”).
Table 33 “DAC_B_CFG_3 register (address 0Eh) bit
Table 19 “COMMON register (address 00h) bit
GAPOUT
VIRES
description”) and to DAC_B_GAIN
BANDGAP
REF.
and register 0Bh; see
CURRENT
SOURCES
ARRAY
001aaj816
DAC
DAC1408D650
(1 %) connected to
Table 14 “I
O(fs)
© NXP B.V. 2009. All rights reserved.
Table 29
) for both DACs
Table 30
O(fs)
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